The invention relates to electrical insulators formed from macromolecular materials having improved properties in particular with respect to partial discharges.
It is known that, owing to imperfect homogeneity, macromolecular insulating materials comprise minute cavities or voids which often contain a gas, especially air. when the insulator is subjected to an electrical field, a fraction of the latter is established between the opposite faces of the voids. These phenomena are referred to hereafter as partial discharges in the insulators. The existence of such partial discharges eventually causes an erosion of the insulating material. In spite of efforts expended for obtaining as homogenous materials as possible, the voids are never entirely eliminated. From a practical standpoint, partial discharges may occur in all insulating systems subjected to high electrical fields. The problem is of the greatest inportance in the case of insulating sheaths for electrical power lines, or capacitor dielectrics.
The invention aims to provide an electrical insulator in which the partial discharges and the resulting erosion are eliminated or at least greatly reduced. The invention aims at obtaining this result without otherwise modifying the properties of the insulator. The invention further aims to provide electrical equipment in which high electrical fields are liable to appear, and comprising at least one electrical conductor, in contact with an insulator, said electrical equipment being efficiently protected against partial electrical discharges which may occur within the insulator.